In hierarchical computer storage systems, intensively used and fast storage are paired with arrays of slower and less frequently accessed data devices. One example of high-speed, expensive memory is a direct access storage device file buffer (DASD). Slower storage devices include tape drives and disk drive arrays, which are less expensive than a DASD.
One such hierarchical storage system is a virtual tape storage system. Such a virtual tape storage system may include, for example, one or more virtual tape servers (“VTS”) in combination with one or more data storage and retrieval systems, such as the IBM TotalStorage® 3494 Enterprise Tape Library. During operation, each virtual tape storage system is communicating data from one or more hosts via a VTS/host communication link, and is providing data to a second VTS for copying via a VTS/VTS communication link.
Data disaster recovery solutions include various “peer-to-peer” copy routines where data is backed-up not only remotely, but also continuously (either synchronously or asynchronously). In order to communicate duplexed data from one host processor to another host processor, or from one storage controller to another storage controller, or some combination thereof, a substantial amount of control data is required for realizing the process. A high overhead, however, can interfere with a secondary site's ability to keep up with a primary site's processing, thus threatening the ability of the secondary site to be able to recover the primary in the event a disaster occurs.
Disaster recovery protection for the typical data processing system requires that primary data stored on primary DASDs be backed-up at a secondary or remote location. The physical distance separating the primary and secondary locations can be set depending upon the level of risk acceptable to the user, and can vary from several kilometers to thousands of kilometers.
New files are received by two or more virtual tape servers from one or more host computers, where each of those virtual tape servers includes one or more virtual host devices having an aggregate VTS/host bandwidth. At the same time, other files are being copied from one VTS to a second VTS using a plurality of virtual copy devices having an aggregate VTS/VTS bandwidth. What is needed is a method to autonomically adjust the VTS/host bandwidth for each attached VTS to thereby adjust the aggregate VTS/VTS bandwidth.